High tensile strength splices for reinforcing bar used in concrete construction have been widely employed. One type using a sleeve with internal deformations employs as a locking element filler metal formed from an exothermic reaction, such molten metal entering the sleeve through a tap hole. When the metal solidifies it forms a lock between the deformation on the interior of the sleeve, and the typical deformations found on the exterior of the reinforcing bar. These types of splices are sold by ERICO Inc. of Solon, Ohio under the trademark CADWELD.RTM.. Examples of such splices may be seen in prior U.S. Pat. Nos. 3,234,603 and 3,255,498 to Leuthy et al.
Another type of reinforcing bar splice that is widely employed is a threaded splice connection. A sleeve with internal threads is threaded into a bar with external threads. One such system which is widely employed and frequently specified is a taper thread system such as that made and sold by ERICO Inc. of Solon, Ohio under the trademark LENTON.RTM..
While each of the above systems may be used to join or extend concrete members already cast, such as in hand holes, pockets, or with dowels or rods projecting from already cast members, such connections are difficult to make since both concrete elements have to be firmly held or supported with respect to each other while the connection is made, and a threaded connection always requires the sleeve or bar to rotate axially and to be tightened to a required torque. Additional concrete then has to be cast around the splice to form the completed structures.
Also, precast members are frequently joined by arc welding steel embedments. However, arc welding requires the parts to be firmly supported and produces heat which may cause damage to the surrounding concrete.
With an improved splicing system steel reinforced precast members could more readily be made and assembled. One attempt at such a splice system is something similar to the grout splice system shown in Yee U.S. Pat. Nos. 3,540,763 and 4,672,212. These patents use a sleeve with internal deformations and a volume stable grout to form a locking element within the sleeve locking on the internal deformations of the bar, much like the metal of the earlier Leuthy et al patents.
When used in forming precast members a splice sleeve and rod is positioned in a form to be cast and the sleeve has to be sealed at the rod end and at the open mouth into which the rod from an adjoining member will project. If it is not properly sealed, concrete when cast will enter the sleeve requiring subsequent time consuming clean out and, since it may not be cleaned out perfectly, lessening the effectiveness of the splice. Moreover, because the sleeve is not connected to the rod and the rod and sleeve are held together only by a boot or seal, and/or external supports such as chairs, the rod and sleeve can easily sag or become misaligned so that two precast elements won't properly fit together and in any event making any joint formed less effective. It would accordingly be desirable to have a grout splice system where the sleeve is readily joined to the rod and becomes an aligned tensile and compression extension thereof, while at the same time sealing the end of the grout receiving sleeve away from the casting form forming the end of the precast member. In this manner stronger precast members could more readily be formed or cast, and also assembled in the field.